UNASSIGNED: The COVID-19 pandemic increased catheter-related bloodstream infections (C-RBSI), but its subsequent impact has not been adequately described. Our hospital has already depicted the effects of the COVID-19 pandemic in the first wave. However, we still do not know whether C-RBSI rates and aetiology are similar to those described before the COVID-19 pandemic. We aimed to evaluate the impact of the COVID-19 pandemic on the evolution of C-RBSI in a large tertiary teaching hospital two years later.
UNASSIGNED: We prospectively collected all confirmed C-RBSI episodes in a clinical microbiology laboratory database by matching blood cultures and catheter tip cultures with the isolation of the same microorganism (s). We compared our C-RBSI incidence rates and aetiology from 2018 to 2023. C-RBSI was defined as bacteremia or fungemia in a patient with clinical manifestations of infection and no other apparent source except the catheter.
UNASSIGNED: During the study period, we collected 556 C-RBSI episodes. C-RBSI incidence rate per 1000 admissions each year was as follows: 2018: 2.2; 2019: 1.7; 2020: 3.29; 2021: 2.92; 2022: 2.69. and 2023: 2.01. Mainly, C-RBSI episodes occurring in critical care units each year were, respectively: 2018: 57 (54.8 %), 2019: 38 (45.2 %), 2020: 89 (63.6 %), 2021: 69 (60.5 %), 2022: 58 (50.9 %) and 2023 (61.4 %). The distribution of microorganisms showed an increase in Gram-negative episodes after the pandemic.
UNASSIGNED: Our study shows an increase in the incidence rate of C-RBSI during the COVID-19 pandemic, with a discrete decrease after that. C-RBSI episodes were mainly caused by coagulase-negative Staphylococci but with a rise in Gram-negative bacilli.

BACKGROUND: Antibiotic Stewardship Programs (ASP) have improved empirical and directed antibiotic treatment in Gram-negative bloodstream infections. A decrease in mortality, readmission, and length of hospitalization has been reported.
METHODS: A pre-post-quasi-experimental study was conducted between November and April 2015-2016 (pre-intervention period), 2016-2017, 2017-2018, and 2018-2019 (post-intervention periods), to analyse the impact of ASP on empirical, directed, and entire treatment optimization, as well as mortality, readmission, and length of hospitalization, in hospitalized patients with Gram-negative bacilli (GNB) bloodstream infections.
RESULTS: One hundred seventy-four patients were included (41 in the pre-intervention group, 38 in the first-year post-intervention group, 50 in the second-year post-intervention group, and 45 in the third-year post-intervention group). There was a significant improvement in directed treatment optimization (43.9% in the pre-intervention group, 68.4% in the first-year post-intervention group, 74% in the second-year post-intervention group, and 88.9% in the third-year post-intervention group, P <0.001), as well as in entire treatment optimization (19.5%, 34.2%, 40.0%, and 46.7%, respectively, P=0.013), with increased optimal directed (adjusted odds ratio [aOR], 3.71; 95% confidence interval [CI], 1.60-8.58) and entire treatment (aOR, 3.31; 95% CI, 1.27-8.58). Although a tendency toward improvement was observed in empirical treatment after ASP implementation, it did not reach statistical significance (41.5% vs. 57.9%, P=0.065). No changes in mortality, readmission, or length of hospitalization were detected.
CONCLUSIONS: ASP implementation improved both directed and entire treatment optimization in patients with GNB bloodstream infections over time. Nevertheless, no improvement was found in clinical outcomes such as mortality, readmission, or length of hospitalization.

BACKGROUND: Non-fermenting Gram-negative bacilli (NFGNB) other than Pseudomonas aeruginosa and Acinetobacter baumannii complex are pathogens of interest due to their ability to cause health-care associated infections and display complex drug resistance phenotypes. However, their clinical and microbiological landscape is still poorly characterized.
METHODS: Observational retrospective study including all hospitalized patients presenting with a positive positive blood culture (BC) episode caused by less common NFGNB over a four-year period (January 2020-December 2023). Clinical-microbiological features and factors associated with mortality were investigated.
RESULTS: Sixty-six less common NFGNB isolates other than Pseudomonas and Acinetobacter species causing 63 positive BC episodes were recovered from 60 patients. Positive BC episodes were predominantly sustained by Stenotrophomonas maltophilia (49.2%) followed by Achromobacter species (15.9%) that exhibited the most complex resistance phenotype. Positive BC episodes had bloodstream infection criteria in 95.2% of cases (60 out 63), being intravascular device (30.2%) and respiratory tract (19.1%) the main sources of infection. Fourteen-day, 30-day, and in-hospital mortality rates were 6.4%, 9.5%, and 15.9%, respectively. The longer time from admission to the positive BC episode, older age, diabetes, admission due to sepsis, and higher Charlson Comorbidity Index were identified as the main predictors of in-hospital mortality.
CONCLUSIONS: Positive BC episodes sustained by NFGNB other than Pseudomonas and Acinetobacter species were predominantly sustained by Stenotrophomonas maltophilia and Achromobacter species, having bloodstream infection criteria in the vast majority of cases. Factors that have emerged to be associated with mortality highlighted how these species may have more room in prolonged hospitalisation and at the end of life for patients with chronic organ diseases.

Testing for dispersal of fluorescent gel from sink drains was sensitive for detection of sinks that dispersed gram-negative bacilli outside the bowl. Reducing the flow rate of sinks with rapid water inflow and/or elimination of obstruction leading to slow outflow was effective in preventing dispersal of fluorescence and gram-negative bacilli.

UNASSIGNED: Recent reports have described the increasing predominance of Gram-negative organisms among invasive bacterial infections affecting preterm infants. This changing pattern of infections is concerning due to the spread of antibiotic resistance among Gram-negatives.
UNASSIGNED: We conducted a single-centre, retrospective cohort study involving very-low-birthweight (VLBW) (<1500 grams) infants born <32 weeks gestation, with culture-proven infections (blood, urine, cerebrospinal fluid [CSF]) in the neonatal intensive care unit from 1 January 2005 to 31 October 2017.
UNASSIGNED: A total of 278 out of 2431 (11.4%) VLBW infants born <32 weeks gestation developed 334 infections, i.e. 52 (15.6%) early-onset infections (EOIs) and 282 (84.4%) late-onset infections (LOIs). The overall incidence decreased from 247 to 68 infections per 1000 infants over the study period, corresponding to reductions in LOI (211 to 62 infections per 1000 infants). A total of 378 bacteria were isolated, i.e. Gram-negatives accounted for 70.9% (45 of 59 [76.3%] EOI; 223 of 319 [69.9%] LOI). Specific resistant organisms were noted, i.e. Methicillin-resistant Staphylococcus aureus (8 of 21 S. aureus infections [38.1%]); Cephalosporin-resistant Klebsiella (18 of 62 isolates [29.0%]) and multidrug-resistant [MDR] Acinetobacter (10 of 27 isolates [37.0%]). MDR organisms accounted for 85 of 195 (43.6%) Gram-negative infections from the bloodstream and CSF. Based on laboratory susceptibility testing, only 63.5% and 49.3% of infecting bacteria isolated in blood were susceptible to empiric antibiotic regimens used for suspected EOI and LOI, respectively.
UNASSIGNED: Gram-negative bacteria are the predominant causative organisms for EOI and LOI and are frequently MDR. Understanding the pattern of antimicrobial resistance is important in providing appropriate empiric coverage for neonatal infections.

OBJECTIVE: Ceftolozane-tazobactam (C/T) is a combination of a cephalosporin and a β-lactamase inhibitor with activity against Gram-negative bacilli (GNB). The study aims were to evaluate the activity of C/T in vitro vs. comparators against clinical GNB isolated from Chinese paediatric patients.
METHODS: From 2017-2021, 660 GNB isolates were collected from 20 hospitals across China. The minimum inhibitory concentrations were tested using a Trek Diagnostic System (Thermo Fisher Scientific). Susceptibility was determined by CLSI broth microdilution and the results were interpreted according to CLSI M100 (2021) breakpoints.
RESULTS: GNB isolates were obtained from paediatric patients < 18 years old, mainly from the bloodstream (n = 146), intraperitoneal cavity (n = 138), lower respiratory (n = 278) and urinary tract (n = 96). Overall, C/T was active against 76.6% of 436 Enterobacterales, with a descending susceptibility rate of 100.0% to S. marcescens, 92.2% to E. coli, 83.3% to K. oxytoca, 66.7% to K. aerogenes, 66.7% to P. mirabilis, 58.6% to K. pneumoniae and 57.1% to E. cloacae. The susceptibility of P. aeruginosa to C/T was 89.4%, which was the highest among the β-lactam antibiotics and was second only to amikacin (92.9%). Isolates of respiratory tract infection (RTI) derived P. aeruginosa were highly susceptible (93.8%) to C/T, while <75% of isolates of RTI derived P. aeruginosa were susceptible to the other β-lactam antibiotics tested, except for ceftazidime-avibactam (91.2%).
CONCLUSIONS: GNBs collected from paediatric patients in China showed a high susceptibility to C/T making this drug combination an effective choice for treating the paediatric population, especially those infected with P. aeruginosa.

BACKGROUND: The landscape of Pseudomonas infective endocarditis (IE) is evolving with the widespread use of cardiac implantable devices and hospital-acquired infections. This systematic review aimed to evaluate the emerging risk factors and outcomes in Pseudomonas IE.
METHODS: A literature search was performed in major electronic databases (PubMed, Scopus, and Google Scholar) with appropriate keywords and combinations till November 2023. We recorded data for risk factors, diagnostic and treatment modalities. This study is registered with PROSPERO, CRD42023442807.
RESULTS: A total of 218 cases (131 articles) were included. Intravenous drug use (IDUs) and prosthetic valve endocarditis (PVE) were major risk factors for IE (37.6% and 22%). However, the prosthetic valve was the predominant risk factor in the last two decades (23.5%). Paravalvular complications (paravalvular leak, abscess, or pseudoaneurysm) were described in 40 cases (18%), and the vast majority belonged to the aortic valve (70%). The mean time from symptom onset to presentation was 14 days. The incidence of difficult-to-treat resistant (DTR) pseudomonas was 7.4%. Valve replacement was performed in 57.3% of cases. Combination antibiotics were used in most cases (77%), with the aminoglycosides-based combination being the most frequently used (66%). The overall mortality rate was 26.1%. The recurrence rate was 11.2%. Almost half of these patients were IDUs (47%), and most had aortic valve endocarditis (76%).
CONCLUSIONS: This review highlights the changing epidemiology of Pseudomonas endocarditis with the emergence of prosthetic valve infections. Acute presentation and associated high mortality are characteristic of Pseudomonas IE and require aggressive diagnostic and therapeutic approach.

OBJECTIVE: Despite the increasing reports of blaNDM in Enterobacterales in Brazil, comprehensive whole genome sequencing (WGS) data remain scarce. To address this knowledge gap, our study focuses on the characterization of the genome of an New Delhi Metallo-β-lactamase (NDM)-1-producing Klebsiella quasipneumoniae subsp. quasipneumoniae (KQPN) clinical strain isolated in Brazil.
METHODS: The antimicrobial susceptibility profile of the A-73.113 strain was performed by agar dilution or broth microdilution following the Brazilian Antimicrobial Susceptibility Testing Committee/European Committee on Antimicrobial Susceptibility Testing recommendations. WGS was performed using the Illumina® NextSeq platform and the generated reads were assembled using the SPAdes software. The sequences obtained were submitted to the bioinformatics pipelines to determine the sequence type, resistome, plasmidome, and virulome.
RESULTS: The A-73.113 strain was identified as KQPN and was susceptible to polymyxins (MICs, ≤0.25 µg/mL), tigecycline (MIC, 0.5 µg/mL), ciprofloxacin (MIC, 0.5 µg/mL), and levofloxacin (MIC, 1 µg/mL). WGS analysis revealed the presence of genes conferring resistance to β-lactams (blaNDM-1, blaCTX-M-15, blaOXA-9, blaOKP-A-5, blaTEM-1), aminoglycosides [aph(3\')-VI, aadA1, aac(6\')-Ib], and fluoroquinolones (oqxAB, qnrS1, aac(6\')-Ib-cr]. Additionally, the presence of the plasmid replicons Col(pHAD28), IncFIA(HI1), IncFIB(K) (pCAV1099-114), IncFIB(pQil), and IncFII(K), as well as virulence-encoding genes fimABCDEFGHIK (type 1 fimbria), pilW (type IV pili), iutA (aerobactin), entABCDEFS/fepABCDG/fes (Ent siderophores), iroE (salmochelin), and allABCDRS (allantoin utilization) was verified. Furthermore, we found that the A-73.113 strain belongs to ST1040.
CONCLUSIONS: Here we report the genomic characteristics of an NDM-1-producing KQPN ST1040 strain isolated from blood cultures in Brazil. These data will enhance our comprehension of how this species contributes to the acquisition and dissemination of blaNDM-1 in Brazilian nosocomial settings.

UNASSIGNED: Nosocomial infectious ventriculitis caused by multidrug-resistant (MDR) Gram-negative bacilli associated with external ventricular drainage (EVD) placement poses a significant mortality burden and hospital costs.
UNASSIGNED: This study aims to analyze the characteristics, ventriculitis evolution, treatment, and outcomes of patients with ventriculitis due to MDR Gram-negative bacilli associated with EVD placement.
UNASSIGNED: A retrospective cohort study focusing on patients with nosocomial infection caused by MDR Gram-negative bacilli while on EVD was conducted from 2019 to 2022. Medical, laboratory, and microbiological records were collected. The antibiotic resistance of the Gram-negative bacilli isolated in the cerebrospinal fluid (CSF) of patients was analyzed. The risk factors were identified using univariate risk models and were analyzed using survival curves (Cox regression). An adjusted Cox proportional hazards model was also constructed.
UNASSIGNED: Among 530 patients with suspected EVD-associated ventriculitis, 64 patients with isolation of Gram-negative bacilli in CSF were included. The estimated mortality was 78.12%. Hemorrhages (intracranial, subarachnoid, and intraventricular) were observed in 69.8% of patients. Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa were the most frequently isolated bacilli. In the univariate analysis, significant risk factors for mortality included arterial hypertension, a Glasgow Coma Scale (GCS) score of ≤ 8, invasive mechanical ventilation (IMV) upon hospital admission and during hospitalization, septic shock, and ineffective treatment. The adjusted Cox proportional hazards model revealed that septic shock (HR = 3.3, 95% CI = 1.5-7.2; p = 0.003) and ineffective treatment (HR = 3.2, 1.6-6.5, 0.001) were significant predictors. A high resistance to carbapenems was found for A. baumannii (91.3%) and P. aeruginosa (80.0%). Low resistance to colistin was found for A. baumannii (4.8%) and P. aeruginosa (12.5%).
UNASSIGNED: Ineffective treatment was an independent hazard factor for death in patients with ventriculitis caused by MDR Gram-negative bacilli associated with EVD.

BACKGROUND: Multiple randomized controlled studies have compared numerous antibiotic regimens, including new, recently commercialized antibiotics in the treatment of nosocomial pneumonia (NP). The objective of this Bayesian network meta-analysis (NMA) was to compare the efficacy and the safety of different antibiotic treatments for NP.
METHODS: We conducted a systematic search of PubMed, Medline, Web of Science, EMBASE and the Cochrane Library databases from 2000 through 2021. The study selection included studies comparing antibiotics targeting Gram-negative bacilli in the setting of NP. The primary endpoint was 28 day mortality. Secondary outcomes were clinical cure, microbiological cure and adverse events.
RESULTS: Sixteen studies encompassing 4993 patients were included in this analysis comparing 13 antibiotic regimens. The level of evidence for mortality comparisons ranged from very low to moderate. No significant difference in 28 day mortality was found among all beta-lactam regimens. Only the combination of meropenem plus aerosolized colistin was associated with a significant decrease of mortality compared to using intravenous colistin alone (OR = 0.43; 95% credible interval [0.17-0.94]), based on the results of the smallest trial included. The clinical failure rate of ceftazidime was higher than meropenem with (OR = 1.97; 95% CrI [1.19-3.45]) or without aerosolized colistin (OR = 1.40; 95% CrI [1.00-2.01]), imipemen/cilastatin/relebactam (OR = 1.74; 95% CrI [1.03-2.90]) and ceftazidime/avibactam (OR = 1.48; 95% CrI [1.02-2.20]). For microbiological cure, no substantial difference between regimens was found, but ceftolozane/tazobactam had the highest probability of being superior to comparators. In safety analyses, there was no significant difference between treatments for the occurrence of adverse events, but acute kidney failure was more common in patients receiving intravenous colistin.
CONCLUSIONS: This network meta-analysis suggests that most antibiotic regimens, including new combinations and cefiderocol, have similar efficacy and safety in treating susceptible Gram-negative bacilli in NP. Further studies are necessary for NP caused by multidrug-resistant bacteria. Registration PROSPERO CRD42021226603.